The present invention relates to hand-held computer terminals and more particularly to hand-held, battery powered computer terminals or the like.
A recent development in data terminal devices has been the introduction of hand-held data terminal devices which are used in data collection and inventory control where the portability of the terminal device is required. Such terminal devices utilize batteries for the power supply. In such battery-operated devices, fast-charging techniques are utilized to reduce the down time that the terminal device is subjected to. In the use of such fast-charging operations, temperature monitoring is critical to prevent cell damage and to provide reliability of the power supply. After reaching a full charge, a battery cell will continue to absorb energy which is turned into heat which may damage the battery cells associated with the power supply. Monitoring the temperature is a much more reliable indicator of a fully-charged battery cell than monitoring the over-voltage condition of the cell. However, accurate and reliable temperature monitoring schemes have been impractical due to cost considerations.
It is therefore a principal object of this invention to provide an apparatus for monitoring the condition of a charging battery cell to indicate the start of an overcharged condition.
It is another object of this invention to provide a battery-temperature sensing apparatus which can be incorporated within the circuitry of a hand-held data processing device.
It is a further object of this invention to provide a battery temperature sensing device which utilizes a flexible portion of a printed circuit board mounted within a portable hand-held data terminal device.
It is a further object of this invention to provide a battery temperature sensing apparatus which is simple in construction and low in cost.